Up in California’s High Sierra, above the dense pine forests, rocky habitats reign. And if you look carefully among the boulders, you might see a pika—a rabbit relative the size of a hamster, with round ears and big eyes.

"Hikers oftentimes see them with little bouquets of wildflowers sticking out of their mouths." Joseph Stewart, a conservation biologist at the University of California Santa Cruz. "Maybe I'm a little biased, other people tell me they're very cute. I find them majestic. I feel like they're the lords of the mountain."

Stewart is also a skilled spotter of pikas. "You could say I've got a little bit of experience with that." Which makes it all the more strange that in five years of surveys—of 64 square miles of high mountain rocky habitats near Lake Tahoe—he found no pikas at all. In an area littered with decades-old pika droppings.

Pikas can still be seen elsewhere in Tahoe, and in other parts of the Sierras. Especially further south, where loftier summits allow pikas to roam higher to escape rising temperatures. But Stewart still worries about their eventual fate.

"We're depriving future generations of the ability to see this critter. And pikas have been around longer than humans have been around. What right do we have to cause pikas and all the other species that are vulnerable to climate change to go extinct?"

Scientific American is part of Springer Nature, which owns or has commercial relations with thousands of scientific publications (many of them can be found at www.springernature.com/us). Scientific American maintains a strict policy of editorial independence in reporting developments in science to our readers.